Officials from Turkey, Finland and Sweden were expected to meet at an undisclosed location in Finland on Friday to discuss security concerns which Turkey raised as a precondition for allowing the two Nordic countries to join the NATO military alliance.

Finland's Foreign Minister Pekka Haavisto said earlier the first meeting between officials would aim to establish contacts and set goals for cooperation that the three countries agreed to by signing a memorandum of understanding at NATO's Madrid summit at the end of June.

The two Nordic countries applied for NATO membership in response to Russia's invasion of Ukraine, but were faced with opposition from Turkey which accused them of imposing arms embargoes on Ankara and supporting groups it deems terrorists.

Turkish Foreign Minister Mevlut Cavusoglu has demanded Sweden and Finland extradite suspects Turkey seeks over terrorism-related charges while the Nordic countries argue they did not agree to any specific extraditions by signing the memorandum.

Finland's foreign ministry remained tight-lipped about Friday's meeting, refusing to reveal its location or even timing.

"This is a matter of security. If we would tell where Turkey's high officials are at which time, it would give quite a careless picture of us," Haavisto's state secretary Jukka Salovaara told Finland's public broadcaster YLE.